Preheat oven to 375°F (190°C). Lightly grease a 9-inch tart pan with a removable bottom.
In a large bowl, whisk together flour, salt, and sugar.
Add cold butter and vanilla extract to the flour mixture. Use a pastry cutter or fingertips to work the butter into the flour until it resembles coarse crumbs.
Press the dough evenly across the bottom and sides of the prepared tart pan. Use a fork to prick the bottom of the crust all over.
Combine golden syrup, lemon juice, zest, and heavy cream in a medium saucepan. Heat over medium, stirring constantly, until well combined.
Bring the syrup mixture to a boil, then reduce the heat and simmer for 2 minutes, stirring constantly.
Remove from heat and stir in fresh breadcrumbs and beaten egg until well incorporated.
Pour the filling into the prepared crust and spread it evenly with a spatula.
Bake for 25 to 30 minutes or until the filling is set and the crust is golden brown.
Allow the tart to cool in the pan on a wire rack before removing it carefully.
Dust with powdered sugar before serving. Enjoy!
